Coupled model of concentration polarization and pore transport in crossflow nanofiltration

✍ Scribed by Subir Bhattacharjee; Jim C. Chen; Menachem Elimelech

• Publisher: American Institute of Chemical Engineers
• Year: 2001
• Tongue: English
• Weight: 553 KB
• Volume: 47
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690471213

✦ Synopsis

Abstract

A coupled model of concentration polarization and pore transport of multicomponent salt mixtures in crossflow nanofiltration rigorously predicts local variations of ionic concentrations, flux and individual ion rejections along a rectangular crossflow filtration channel by a coupled solution of the convective‐diffusion and extended Nernst‐Planck equations. Coupling the pore transport model with the multicomponent convective‐diffusion equation in the concentration polarization layer provides a comprehensive understanding of the interplay between concentration polarization and salt rejection. The coupled model is used to predict the local variations of ion rejection, permeate flux and mixture composition in a rectangular crossflow filtration channel for three‐component salt mixtures. The total membrane surface concentration of the ions and the ratio of different ions in the mixture (salt ratio) can change considerably along a crossflow filtration channel, and, consequently, cause remarkable variations in intrinsic ion rejections with axial position in the channel.